Group III, "synthetic oils", refined from old school dead dinosaur technology crude oil, or cutting edge technology Group IV PAO true synthetic oils?Yup, Pennzoil Ultra and Platinum, Castrol Edge, Valvoline Synpower, Quaker State Ultimate Durability and the 4 flavors of Mobil1 available at most WalMarts are absolute junk products.
Actually these are all great motor oils that are likely far better than any car needs, especially if paired with a sensible oil change interval. You're welcome to spend two or three times the WalMart price on a "true" synthetic. But I bet your car won't last any longer.
Research the differences. I think you may find they are worth it. There's much more to a motor oil than merely how long the engine will last.